Sheet material feeder

ABSTRACT

A sheet material feeding device includes a rotatable driver member axially supported at a position spaced above a top sheet of a stack of sheets in a sheet tray. A feed member is pivotally connected to the driver member in an eccentric relationship relative to the axis of the driver member. In operation, the driver member moves the feed member in a forward feed stroke during a portion of each revolution of the driver member and moves the feed member in a rearward return stroke during the remaining portion of the revolution. The feed member extends outwardly and angularly downwardly from the driver member towards the top sheet of the stack in the direction of movement of the sheet. The free end of the feed member adjacent the top sheet is provided with a frictional element for engaging and advancing the sheet in response to a forward stroke of the feed member and is raised out of engagement with the sheet in response to a rearward stroke of the feed member to avoid retrograde movement or streaking of the sheet being fed.

United States Patent [191 Songer [451 Oct. 7, 1975 [73] Assignee:Addressograph Multigraph Corporation, Cleveland, Ohio Nov. 5, 1973 Appl.No.: 412,533

22 Filed:

[52] US. Cl. 271/42; 221/268; 271/251 [51] Int. Cl. BGSI-I 3/36 [58]Field of Search 271/42, 128, 130, 109, 271/18,120, 119,19-25, 251, 266,267,140; 221/268, 270, 272-274 FOREIGN PATENTS OR APPLICATIONS UnitedKingdom 271/109 Primary Examiner-Evon C. Blunk Assistant ExaminerBruceH. Stoner, Jr. Attorney, Agent, or FirmRussell L. Root; Sol L.Goldstein; Ray S. Pyle [57] ABSTRACT A sheet material feeding deviceincludes a rotatable driver member axially supported at a positionspaced above a top sheet of a stack of sheets in a sheet tray. A feedmember is pivotally connected to the driver member in an eccentricrelationship relative to the axis of the driver member. In operation,the driver member moves the feed member in a forward feed stroke duringa portion of each revolution of the driver member and moves the feedmember in a rearward return stroke during the remaining portion of therevolution. The feed member extends outwardly and angularly downwardlyfrom the driver member towards the top sheet of the stack in thedirection of movement of the sheet. The free end of the feed memberadjacent the top sheet is provided with a frictional element forengaging and advancing the sheet in response to a forward stroke of thefeed member and is raised out of engagement with the sheet in responseto a rearward stroke of the feed member to avoid retrograde movement orstreaking of the sheet being fed.

5 Claims, 5 Drawing Figures US. Patent Oct. 7,1975

SHEET MATERIAL FEEDER BACKGROUND OF THE INVENTION Devices for feedingsingle sheets from a stack disposed in a stack receiving tray intovarious types of utilization devices are well known. Such sheet feedingdevices frequency are equipped with a pair of driven friction wheels orrollers mounted in axially spaced positions on a shaft which is disposedtransverse to the direction of movement of the sheet. The wheels whichrest on the top of the stack or which can be spring biased toward thestack are intermittently driven by suitable gearing or flexibleconnections to a drive means in the utilization device to feedindividual sheets to the device at time spaced intervals. These sheetfeeding devices are mounted on the frame of the apparatus adjacent thefeed-in station in a fixed position. The platform of the stack receivingtray lies in a plane parallel to the plane passing through the contactpoints between the feed wheels and the top sheet.

One of the problems of known sheet feeding apparatus is the skewedfeeding of the sheet into the utilization device. This skewed feedingfrequently results from moving one side of the sheet at a faster speedthan the other side. This causes the leading edge of the sheet to bepresented at an angle to the feed-in station with the result that itfrequently becomes fouled in the vari ous transporting means within theapparatus.

There are a number of conditions in both the paper stack and the traywhich cause skewed feeding. The condition and the location of the feederwheels can cause the defective feeding. For example, a lack ofuniformity in the wear of the wheel surfaces results in changing theperipheral speed of each of the wheels so that one side of the sheet ismoved at a different speed than the other. Also, if the wheels are notsymmetrically placed along the transverse width of the sheet, improperfeeding can occur.

In addition, the surface finish of the sheet bears an importantrelationship to the uniformity of feeding because the greater thecoefficient of friction between the sheet surfaces, the more criticalthe adjustment of the feeder wheels. The stiffness and the basic weightof the sheet are important factors since limp sheets or thin materialwill more readily yield and buckle along a line parallel to thedirection of the movement of the sheet in response to improperlyadjusted feeder wheels.

While these known types of sheet feeders have been more or lesssatisfactory for operation under certain conditions, they are, to agreater or lesser extent, relatively difficult to service and maintainin proper adjustment, cumbersome, and costly to manufacture.

SUMMARY OF THE INVENTION This invention relates to sheet feedingapparatus and, more particularly, to a device for advancing individualsheets from the top of a stack of sheets to feed-in mechanism of autilizatin device.

An object of the invention is to provide a new and improved sheet feederdevice which is inexpensive, compact and capable of feeding intermixedsheets of different weights and sizes.

Another object of the invention is to provide a sheet feeder whichincludes only a single moving element which provides simplified operatoradjustment, minimum servicing requirements and avoids skewed feed ing ofthe sheets.

Another object of the invention is to provide a sheet feeder which, withbut minor modifications, provides a wide range of feed rates i.e., thedistance and the speed at which the sheet is advanced from the stack tothe feed-in rollers of a utilization device.

Another object of the invention is to provide a sheet feeder comprisinga single feed member. The feed member is mounted at a lateral angle withrespect to a vertical side guide of the sheet tray so as to urge a sideedge of the sheet being fed against the side guide to maintain accurateregistration of the sheet during its advancement from the stack.

Another object of the invention is to provde a sheet feeder in which arotary driver moves the feed member through a forward feed stroke and areturn rearward stroke during each revolution of the driver. During theforward stroke a frictional element on the feed member engages andadvances the top sheet of the stack and during rearward movement thefrictional element is raised out of engagement with the sheet by virtueof the velocity at which the driver is rotated.

Another object of the invention is to provide a sheet feeder in whichthe feed member may be arranged for advancing a sheet from the stack toa feed-in mechanism in each forward stroke of the feed member, or it maybe arranged to apply a series of strokes to the sheet to cause the sheetto advance with a stop and start motion.

The foregoing objects of the invention are attained by providing a sheetfeeding device comprising a rotary driver member supporting aneccentrically mounted feed member having a frictional element thereon.Through the rotary drive and the eccentric motion, the feed member ismoved through a forward stroke to urge the frictional element downwardlyand forwardly to engage and advance the top sheet to be fed from thestack. During the rearward or return stroke of the feed member thefrictional element is raised out of engagement with the sheet to avoidstreaking or disturbing the sheet being fed. The raising of thefrictional element out of engagement with the sheet during the rearwardstroke of the feed member results from the relatively high velocity ofrotation of the driver member, thereby eliminating the need for anyadditional controls or mechanism for raising the frictional elementduring the rearward stroke of the feed member.

IN THE DRAWING FIGS. 1 4 are schematic side elevations of a sheetmaterial feeding device in accordance with the practice of the presentinvention showing in sequence a complete feed cycle for advancing a topsheet from a stack of sheets; and

FIG. 5 is a top plan, partially broken away, showing the mounting anddrive arrangement of the sheet feeding device in a start position.

DESCRIPTION OF THE PREFERRED EMBODIDMENT The sheet feeding device iscapable of feeding intermixed sheets of various weights and sizes and,as shown in FIG. 5, will be described for feeding narrow sheets 10 fromthe top of a stack of wider sheets 12 positioned on a sheet tray 14.

The tray 14- is provided with a pair of side guides 16 (only one shownin FIG. 5) for maintaining both sides of the stack of sheets 12 inalignment, and the narrow sheets 10 are positioned with only one sideedge in alignment against the side guide 16 shown in FIG. 5.

A drive motor 18 is mounted on the outer surface of the side guide 16and includes a drive shaft 20 projecting through an opening in the sideguide 16 extending over the stack of sheets. The motor 18 is angularlymounted with respect to the side guide 16 (see FIG. such that the shaft20 and the side guide 16 form an acute angle therebetween in a directionof movement of the sheet, for a purpose to be explained hereinafter.

A driver member or disc 22 is secured on the drive shaft 20 such thatthe axis of the driver member 22 is substantially transverse to thedirection of movement of the sheet. A feed member 24 is pivotallyconnected at one end to the driver member 22 in an eccentricrelationship relative to the axis of the driver member 22. The feedmember 24 is provided at its other end with a frictional element 26 forengaging and advancing the top sheet to be fed.

The feed member 24 extends downwardly from the driver member 22 andforwardly in the direction of sheet feed towards the lead edge of thestack of sheets to provide a feed angle ranging from to 45 between thefeed member 24 and the top of the stack of sheets. The frictionalelement 26 normally rests by gravity on the top sheet of the stack at apoint substantially displaced from a point beneath the axis of thedriver member 22. In operation, rotation of the driver member 22 impartsto the free end of the feed member 24 and, specifically, to thefrictional element 26 an only partially constrained orbital motionhaving a reciprocatory component along the plane of the top of the stackof sheets. If the sheet feeder is used in association with a sheet traythat is periodically raised to maintain the height of the stack at aproper feeding level, the feed angle will remain fairly constant.However, if the sheet tray is fixed, the feed angle will vary as thestack is depleted or replenished and the feed member 24 will effectivelyadvance the top sheet so long as the feed angle is within the aboverange.

The frictional element 26 may be made of any suitable material having ahigh coefficient of friction, such as silicone rubber, and it may beshaped in the form of a sphere, disc, tube, flat pad or any otherdesirable configuration.

Referring now to FIGS. 1 4, there is shown a complete sheet feed cyclein response to a single revolution of the driver member 22. Thus, as thedriver member 22 is rotated in the direction of the arrow the pivotalconnection of the feed member 24 is moved from a position A shown inFIG. 1 through positions B, C and D shown in FIGS. 2 4 respectively, andreturns to the position A.

With the pivotal connection of the feed member 24 at the position A, thefeed member 24 is in a start or neutral position and the frictionalelement 26 rests on the top sheet 10 of the stack. As the driver member22 is rotated and the pivotal connection moved to the position B (FIG.2) the feed angle of the feed member 24 is increased such as to urge thefrictional element 26 downwardly into feeding engagement with the sheet10.

During continued rotation of the driver member 22, as the pivotalconnection moves from the position B towards the position C, the feedmember 24 is moved through a forward stroke and the top sheet isadvanced slightly by the frictional element 26 as illustrated in FIG. 3.When the pivotal connection arrives at the position C (FIG. 3) the feedmember 24 has completed its forward stroke and the lead edge of thesheet 10 has been advanced a sufficient distance to be gripped by a pairof feed-in rollers 28 and 30.

Further rotation of the driver member 22 moves the pivotal connection tothe position D (FIG. 4) and raises the frictional element 26 out ofengagement with the sheet 10 to thereby avoid streaking or disturbingthe top sheet in its travel through the nip of the feed-in rollers 28and 30. As the driver member 22 completes the revolution, moving thepivotal connection from the position D to the position A of FIG. 1, thefeed member 24 is.moved in a rearward stroke while maintaining thefrictional element 26 out of contact with the top sheet.

Arrival of the pivotal connection at the position A restores the feedmember 24 to the start position of FIG. 1, with the frictional element26 lowered into contact with the next sheet at the top of the stack inreadiness for a subsequent sheet feed operation.

The lifting or raising of the frictional element 26 out of engagementwith the top sheet during the rearward stroke of the feed member 24 isachieved as a result of the relatively high velocity of rotation of thedriver member 22. Thus, with the motor 18 operating at approximately300-400 R.P.M., the velocity at which the driver member 22 is rotated issufficiently high so that the frictional element 26 tends to be drawntowards the pivotal connection of the feed member 24 and in so doing iscaused to raise up and out of contact with the stack of sheets.

As shown in FIG. 5, the angular mounting of the motor 18 referred toabove provides for also angularly mounting the feed member 24 such thatit extends forwardly towards the front of the stack and outwardlytowards the side guide 16.

Because both side edges of the narrow sheets 10 are not held inalignment by the side guides 16, as are the side edges of the widersheets 12, the angular position of the feed member 24 is effective tourge the side edge of the narrow sheet tight up against the side guide16 of FIG. 5, to thereby maintain alignment of the narrow sheet duringits advancement from the stack.

While the foregoing describes a feeding operation in which a sheet isfed in each cycle or revolution of the driver member 22, the feedingdevice may also be utilized for feeding a sheet by applying a series ofstrokes thereto to advance the sheet with a stop and start motion.

In those instances, for example, wherein the feed-in rollers 28 and 30of a utilization device are spaced a substantial distance from the leadedge of the sheets in the stack, a single revolution of the drivermember 22 and a single forward stroke of the feed member 24 might failto advance the top sheet a sufficient distance so as to present the leadedge of the sheet into the nip of the feed-in rollers. In such as casethe feed member 24, during continued rotation of the driver member 22,applies a series of feed strokes to the sheet. Thus, the sheet isadvanced during the forward stroker and it is at rest during therearward stroke because of the frictional element being raised out ofcontact with the sheet. By applying a series of strokes in this mannerduring continued rotation of the driver member 22, the sheet continuesto be advanced until its lead edge 'arrives at and is gripped by thefeed-in rollers.

The sheet feeding device is susceptible to several modifications forincreasing the feed rate (distance and speed at which the sheet isadvanced) and for providing a larger capacity for the stack of sheets tobe fed from the tray 14.

In this regard, the feed rate may be increased by increasing the size ofthe driver member 22 so that the pivotal connection of the feed member24 is positioned a greater distance from the axis of the driver member.Alternately, the feed rate may be increased by increasing the R.P.M. ofthe driver member 22 and the weight of the frictional element 26.

To provide for the reception of a larger stack of sheets in the tray 14it is merely necessary to increase the distance of the drive shaft abovethe stack and, of course, lengthen the feed member 24 accordingly tomaintain a proper feed angle of the feed member 24 with respect to thestack.

It will be appreciated that the sheet material feeding device of thepresent invention provides a compact feeder providing simplifiedoperator adjustment and minimum servicing requirements. The singlemoving sheet feed member 24 is positive in operation to advance the topsheet and to register and maintain the sheet in alignment during itsmovement from the stack, while avoiding skewed feeding of the sheet.Additionally, streaking or disturbing the sheet being fed is precludedas a result of the frictional element 26 being raised out of contactwith the sheet during the rearward stroke of the feed member 24.

What is claimed is:

l. A sheet material feeding device for advancing a top sheet from astack of sheets, comprising:

a driver member supported for rotation about an axis transverse to thedirection of movement of the sheet at a position spaced above the stackof sheets;

an elongate feed member connected at one end eccentrically to the drivermember solely by a pivotal connection and extending downwardly andforwardly from the driver member in the direction of feed of the sheetto normally rest at its other end by gravity upon the top surface of thesheet at a point substantially displaced from a point beneath the drivermember axis; said feed member being movable through a forward feedstroke and a rearward return stroke and including at said other end africtional element for advancing the top sheet from the stack; and

means for rotating the driver member at a velocity sufficient to impartto the frictional element a partially constrained orbital motion havinga reciprocatory component along the plane of the top of the stack ofsheets for moving the frictional element into engagement with the topsheet during the forward stroke of the feed member and for moving thefrictional element out of engagement with the top sheet duringsubstantially the complete rearward stroke of the feed member in eachrevolution of the driver member.

2. A sheet material feeding device as set forth in claim 1 in which thedownwardly and forwardly extending feed member forms a feed angle ofbetween 10 and 45 with the top of the stack of sheets.

3. A sheet material feeding device as set forth in claim 1 in which thefrictional element comprises silicone rubber.

4. A sheet material feeding device as set forth in claim 1 in which themeans for rotating the driver member includes a motor having a driveshaft for axially supporting the driver member.

5. A sheet material feeding device as set forth in claim 1 in which thestack of sheets is positioned in a sheet tray having a side guide forregistering one side of the stack; and

said feed member extends in the direction of movement of the sheet andangularly outwardly towards the side guide to urge a side edge of thetop sheet into alignment against the side guide during advancement ofthe sheet from the stack.

1. A sheet material feeding device for advancing a top sheet from astack of sheets, comprising: a driver member supported for rotationabout an axis transverse to the direction of movement of the sheet at aposition spaced above the stack of sheets; an elongate feed memberconnected at one end eccentrically to the driver member solely by apivotal connection and extending downwardly and forwardly from thedriver member in the direction of feed of the sheet to normally rest atits other end by gravity upon the top surface of the sheet at a pointsubstantially displaced from a point beneath the driver member axis;said feed member being movable through a forward feed stroke and arearward return stroke and including at said other end a frictionalelement for advancing the top sheet from the stack; and means forrotating the driver member at a velocity sufficient to impart to thefrictional element a partially constrained orbital motion having areciprocatory component along the plane of the top of the stack ofsheets for moving the frictional element into engagement with the topsheet during the forward stroke of the feed member and for moving thefrictional element out of engagement with the top sheet duringsubstantially the complete rearward stroke of the feed member in eachrevolution of the driver member.
 2. A sheet material feeding device asset forth in claim 1 in which the downwardly and forwardly extendingfeed member forms a feed angle of between 10* and 45* with the top ofthe stack of sheets.
 3. A sheet material feeding device as set forth inclaim 1 in which the frictional element comprises silicone rubber.
 4. Asheet material feeding device as set forth in claim 1 in which the meansfor rotating the driver member includes a motor having a drive shaft foraxially supporting the driver member.
 5. A sheet material feeding deviceas set forth in claim 1 in which the stack of sheets is positioned in asheet tray having a side guide for registering one side of the stack;and said feed member extends in the direction of movement of the sheetand angularly outwardly towards the side guide to urge a side edge ofthe top sheet into alignment against the side guide during advancementof the sheet from the stack.